Sir Stelios Haji-Ioannou, easyJet’s founder, has complained that the “shareholder spring” — which saw Aviva chief executive Andrew Moss quit and put pressure on William Hill boss Ralph Topping about the amount he was paid — had made absolutely no impact on the budget airline.

“Surely the shareholder activism has left a mark somewhere? Apparently not,” Sir Stelios, easyJet’s biggest shareholder, said. “We still have three confusing methods to calculate return on capital employed,” he said, which chairman Sir Mike Rake “has chosen as the metric for bonus payments”.

The airline, in response to previous complaints from Sir Stelios, hired Deloitte to examine its accounting.

Sir Stelios, however, dismissed this by saying: “The latest wheeze is to get another expensive set of advisers — Deloitte — to tell us something we already know: these payments are just too high.”

His comments came as easyJet said an increased number of business travellers helped it to narrow the half-year loss in what is traditionally — for airlines — the tough six months to April. The pre-tax loss in the six months to April fell 27% to £112 million.

Sir Stelios said that was “still no reason to pop champagne corks”. But chief executive Carolyn McCall said: “The economic environment remains uncertain, and the aviation industry faces headwinds such as the recent increase in air passenger duty. However, easyJet is well positioned to deliver good results for shareholders.”